378 



SPECIFIC MICRO-ORGANISMS 



as are all the spirochetes, and has a very slender flagellum at each 

 end. The usual motion is that of rapid rotation on the longitudinal 

 axis with progression, but at times there is gross bending of the 

 filament, especially when the organism is living under unfavorable 



conditions. The mode of division 

 is a somewhat vexed question as it 

 is in regard to the whole group of 

 spirochetes. Transverse and longi- 

 tudinal division have been de- 

 scribed. Probably the weight of 

 authority^ now favors transverse 

 division as the sole mode of multi- 

 plication, although able adherents 

 to the opposite view are not lack- 

 ing. The refractive index of the 

 filament is not very much greater 

 than that of serum, so that the 

 unstained organism is difficult tq 

 see by direct illumination. Dark- 

 field illumination is more satis- 

 factory. Sp. pallida in film prep- 

 arations stains with difficulty by 

 ordinary methods. Schaudinn em- 

 ployed Giemsa's modification of 

 the Romanowsky stain. Good re- 

 sults are obtained by staining 

 with solutions of the Romanowsky 

 staining principles in methyl alcohol provided an excess of me- 

 thylene- violet be present (see p. 44). Tunninclifl^ recom- 

 mends staining with a mixture of saturated alcohoHc solution of 

 gentian violet, i part, in 5 per cent carbolic acid, 9 parts. Thin 

 films are essential but staining process requires only a few seconds. 



Fig, 151. — rFilm preparation from 

 a genital syphilitic papule; in the 

 center are two specimens of Spiro- 

 chceta pallida, the other three are 

 specimens of Spirochata refringens. 

 (After Schaudinn and Hoffmann.) 



' Journ. Exp. Med., 1911, Vol. XIV, p. 99; 1912, Vol. XV, p. 90. 

 ^Journ. A. M. A., 1912, Vol. LVIII, p. 1682. 



